Environmental guidance for your business in Northern Ireland & Scotland

Composting leachate

Composting leachate. Compost handlingComposting leachate

What you must do

You must hold a waste management licence or exemption to carry out composting activities. In Scotland, only meat excluded catering waste can be composted under an exemption. You must also meet your requirements under the Duty of Care.

If you compost catering waste, you must also comply with Animal by-products regulations.

Animal by-products and food waste

Catering waste

You must ensure that leachate or contaminated run-off does not cause any pollution to land, surface, or groundwater pollution.

Preventing water pollution

Land contamination

You must locate all compost treatment areas on waterproof, weatherproof surfaces with sealed drainage.

Trade effluent - managing liquid wastes

Contact your environmental regulator

In Northern Ireland you must have a discharge consent, groundwater authorisation or a pollution prevention and control (PPC) permit before you discharge anything other than clean uncontaminated water to the environment. This includes sewage, trade effluent or contaminated surface run-off.

NIEA: Regulation of water discharges

In Scotland, if you discharge anything to the water environment you may require an authorisation from SEPA. Some discharges are authorised if you comply with the general binding rules (GBR). In such cases, you do not need to apply for authorisation from SEPA. See SEPA: Water - Controlled Activities Regulations (CAR). 

SEPA: CAR – A practical guide (Adobe PDF - 562KB)

You must comply with all the conditions of your authorisation, permit or consent.

You must ensure that any contaminated water or leachate is only taken off-site by a business that holds a waste carrier's registration or waste management licence or an exemption.

Waste carriers, brokers and dealers

You must keep all leachate separate from treated compost. This prevents contamination.

Good practice

Set up a system to hold and manage leachate. This could consist of a containment tank or a lagoon.

You must measure and detect when storage systems are nearly full. Plan collections or treatment in advance to minimise the risk of pollution from overflowing storage systems.

Locate your composting facilities inside and under cover. This will prevent rainwater accessing your facilities, and will reduce the volumes of leachate you have to deal with. If you cannot locate your facilities inside, cover your compost with sheeting to protect it from rainwater.

Minimise the time you store leachate on your site. This will reduce the risk of odours.

In certain situations, you may be able to recirculate the leachate into your compost to maintain the correct moisture balance.

Store all chemicals in an area where spills can be contained. This should be within a secondary containment system (SCS), such as a bund. The SCS should be able to contain at least 110% of the volume of the largest tank or 25% of the total volume likely to be stored, whichever is greater.

Further information

Association for organics recycling

Read about More waste treatment processes on NetRegs

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NIEA - Apply online

SEPA - Application forms